The present invention is directed to techniques for separating modules on a wafer, particularly for use in creating wafer level assembly of electro-optical modules with manageable electrical input-output, and the structures formed thereby. The present invention is further directed to providing a mechanical support ledge for integrating an optical module with another structure, e.g., a circuit board.
One obstacle encountered in integrating electrical devices with optical components on a wafer level is how to manage the electrical connections. Typical wafer assembly and separating can yield an excellent optical assembly, but with no feasible location for electrical connections, as shown in FIG. 1. In FIG. 1, the module includes an active element 10 mounted on a submount 20 and an optics block 39 with an optical element 40 thereon. Interconnection lines 22 are formed on the submount 20 to provide electrical signals to and/or from the active element 10. The active element 10, e.g., a vertical cavity surface emitting laser (VCSEL), can bonded to the submount 20 at the wafer level, optics and any spacers aligned thereto and integrated therewith. When the individual modules are separated, the electrical connections 22 to the active element 10 are difficult to access.
Another problem arises when attempting to integrate optical element elements formed on a wafer level with planar systems, such as a printed circuit board, or any system which is not to continue the stacked structure of the wafer level constructions. Support and alignment are both issues in this integration.
One potential solution is to assemble the optics and spacers at the wafer level, then separate and bond to the individual submounts. However, this does not take fill advantage of wafer level assembly.
The present invention is therefore directed to methods and structures of providing interconnections to electro-optical elements in an electro-optical module formed on a wafer level which overcome at least one of the above disadvantages.
The present invention is also directed to methods and structures of providing alignment and support for wafer based integrated optical subassemblies with non-stacked systems that overcome at least one of the above disadvantages.
At least one of the above and other objects may be realized by providing a method of creating an electro-optic module including providing an active element wafer having a plurality of active elements thereon; aligning a feature wafer having features thereon to the active element wafer, providing an electrical bonding pad on at least one of the active element wafer and the feature wafer, attaching the feature wafer and the active element wafer to form an integrated wafer, and separating dies from the integrated wafer, at least one die including at least one active element and a feature, said separating including separating along different vertical paths through the integrated wafer such that at least a portion of the wafer having the electrical bonding pad extends beyond the other wafer.
At least one of the above and other objects may be realized by providing an integrated electro-optical module including an active element on a first substrate, a feature on a second substrate, a bonding pad on one of the first and second substrates, the first substrate and the second substrate being attached in a vertical direction to one another, a portion of the first and second substrates having the bonding pad thereon extending further in at least one direction than the other substrate.
At least one of the above and other objects may be realized by providing an apparatus including a planar structure having a hole therein, an optical element formed on a surface of a substrate, the surface having the optical element thereon extending through the hole of the planar structure, a mounting surface, integrated with the substrate having the optical element, the mounting surface extending in at least one direction beyond the substrate; and an attachment mechanism securing the optical element to the planar structure via the mounting surface.
These and other objects of the present invention will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating the preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.